Ad-hoc networks are convenient since they are dynamically formed even when a communication apparatus is added to or removed from the network. Routing methods for ad-hoc networks include a plurality of types of methods such as reactive type methods and proactive type methods, and various routing protocols have been developed. The Ad hoc On-Demand Distance Vector Algorithm (AODV) is an example of a reactive-type routing protocol.
In a network that uses a reactive-type routing protocol, a routing table is created after a transmission request is generated. For example, a route controlling method has been created wherein, in searching for a route from a source apparatus to a destination apparatus, flooding is applied to a request in a direction from the source apparatus to the destination apparatus, and the destination apparatus applies flooding to a reply to the request in a direction toward the source apparatus. In this method, when a route controlling apparatus receives a request or a reply from an adjacent node, the route controlling apparatus stores the information of a route that includes the adjacent node.
Meanwhile, in a network that uses a proactive-type routing protocol, routes are determined before a communication is performed. The Optimized Link State Routing (OLSR) is an example of proactive-type routing protocols. In the using of a proactive-type protocol, apparatuses that participate in the ad-hoc network periodically transmit a Hello frame. The Hello frame includes the information of a source communication apparatus that is the source of the Hello frame and a portion of the route information stored by the source communication apparatus. Using Hello frames, apparatuses that participate in the ad-hoc network determine a route by exchanging route information of the network.